Regulating COOH Intermediate via Rationally Constructed Surface‐Active Sites of Bi 2 WO 6 for Solar‐Driven CO 2 ‐to‐CO Production

Abstract Solar‐driven CO 2 reduction holds great promise for sustainable energy, yet the role of atomic active sites in governing intermediate formation and conversion remains poorly understood. Herein, a synergistic strategy using Ni single atoms (SAs) and surface oxygen vacancies (O v ) is reported to regulate the CO 2 reduction pathway on the Bi 2 WO 6 photocatalyst. Combining in‐situ techniques and theoretical modeling, the reaction mechanism and the structure‐activity relationship is elucidated. In‐situ X‐ray absorption spectroscopy identifies Bi and Ni as active sites, and in‐situ diffuse reflectance infrared Fourier transform spectroscopy demonstrates that adsorption of H 2 O and CO 2 readily forms CO 3 2− species on the O v ‐rich catalyst. Optimally balancing Ni SAs and O v lowers the energy barrier for the formation and dehydration of a key COOH intermediate, leading to favorable CO formation and desorption. Consequently, a superior CO production efficiency of 53.49 µmol g ‒1 is achieved, surpassing previous reports on Bi 2 WO 6 ‐based catalysts for gas‐phase CO 2 photoreduction.